title: Changes in renal vessels following the long-term administration of an angiotensin II receptor blocker in Zucker fatty rats.
abstract: BACKGROUND
  The nephro-protective effects of angiotensin II receptor blockers (ARBs) are widely known; however, there are few reports of long-term effects focusing on the renal vessels. We studied afferent arteriolar changes induced by the long-term administration of an ARB.
  
  
  METHODS
  Thirty-two 6-week-old male Zucker fatty rats (ZFRs) were divided into following four groups (n = 8 in each): ZFR Group and ZFR+High Group fed a standard or high-salt diet, respectively; ZFR+ARB Group and ZFR+High+ARB Group fed a standard or high-salt diet with ARB (Olmesartan, 5 mg/kg/day), respectively. Blood pressure, proteinuria, morphological examinations and glomerular haemodynamics in vivo were studied.
  
  
  RESULTS
  Marked proliferative changes in the afferent arteriolar smooth muscle cells (SMCs) were frequently observed in the two groups given ARBs; in the ZFR+ARB group (77.3±10.3%) compared with the two groups without ARB (1.7%, p < 0.005; 1.2%, p < 0.0005) and 37.4±15.6% in the ZFR+High+ARB group. Proteinuria markedly decreased in the groups treated with ARBs, but the glomerular erythrocyte velocities showed no differences.
  
  
  CONCLUSIONS
  Our findings indicate that long-term ARB administration induced unusual proliferative changes in SMCs of afferent arterioles of ZFRs. These changes could narrow arteriolar lumens and reduce intraglomerular pressure, but they could cause also irreversible damage to the arterioles.
authors.affiliation: Department of General medicine and Emergency care, Faculty of Medicine, Toho University, Tokyo, Japan. kazunaka@med.toho-u.ac.jp
authors.forename: Kazushige
authors.initials: K
authors.lastname: Nakanishi
authors.forename: Yohko
authors.initials: Y
authors.lastname: Nagai
authors.lastname: Honglan Piao
authors.forename: Tatsuo
authors.initials: T
authors.lastname: Akimoto
authors.forename: Hirohito
authors.initials: H
authors.lastname: Kato
authors.forename: Nadezhda
authors.initials: N
authors.lastname: Yanakieva-Georgieva
authors.forename: Yukio
authors.initials: Y
authors.lastname: Ishikawa
authors.forename: Kastunori
authors.initials: K
authors.lastname: Yoshihara
authors.forename: Kinji
authors.initials: K
authors.lastname: Ito
authors.forename: Nobuaki
authors.initials: N
authors.lastname: Yamanaka
authors.forename: Takashi
authors.initials: T
authors.lastname: Oite
mesh_terms: D047228:Angiotensin II Type 1 Receptor Blockers / Q000008:administration & dosage* / Q000494:pharmacology*; D000818:Animals; D001160:Arterioles / Q000187:drug effects* / Q000473:pathology; D004912:Erythrocytes / Q000187:drug effects / Q000473:pathology; D005455:Fluorescent Antibody Technique; D007093:Imidazoles / Q000008:administration & dosage* / Q000494:pharmacology*; D007668:Kidney / Q000098:blood supply* / Q000187:drug effects* / Q000473:pathology; D007678:Kidney Glomerulus / Q000098:blood supply / Q000187:drug effects / Q000473:pathology; D008297:Male; D018613:Microscopy, Confocal; D032389:Myocytes, Smooth Muscle / Q000187:drug effects / Q000473:pathology; D051381:Rats; D011924:Rats, Zucker; D012083:Renin / Q000378:metabolism; D017673:Sodium Chloride, Dietary / Q000008:administration & dosage / Q000494:pharmacology; D013777:Tetrazoles / Q000008:administration & dosage* / Q000494:pharmacology*
chemical_list: D047228:Angiotensin II Type 1 Receptor Blockers; D007093:Imidazoles; D017673:Sodium Chloride, Dietary; D013777:Tetrazoles; C437965:olmesartan; D012083:Renin